The present invention relates generally to reclosable flexible containers and in particular to reclosable flexible containers having continuous fastener profiles affixed to the exterior of the container.
In the manufacture of reclosable plastic bags, bags are usually formed with a folded bottom edge and with side edges sealed to each other about their periphery. Flexible reclosable fastener strips are usually sealed inside the bag near the bag opening. The bag bodies are formed of a thin, lightweight plastic film which is extruded separately from the fastener. The fastener strips are extruded with a process that provides interlocking rib and groove elements carefully shaped and sized so that they will interlock when pressed together and will separate when pulled apart. These fastener strips have webbed portions which are sealed to the inside of the bag. Alternatively, continuous fastener profiles may be integrally formed in the plastic film as seen in U.S. Pat. No. Re. 28,959, Naito. However, problems have appeared in the past in the sealing of fastener strips to the inside of the bag walls. Further, it has been found that forming the fastener strips integrally with the bag walls tends to reduce the speed of manufacture.
It has been known in the past to join sheets of plastic film utilizing clamps or fasteners which grip multiple layers of plastic film from the outside. An example is U.S. Pat. No. 3,893,212, Curry. However, despite a wide variety of configurations of reclosable fastener containers found in the prior art, the use of flexible continuous fastener strips sealed to the exterior of reclosable flexible containers which interlock through the walls of the container and do not inadvertently open, has not been shown. The use of flexible fastener strips sealed to the outside of the container makes possible wide spread utilization of the present invention in commercial applications such as food storage bags.
Accordingly, it is an object of the present invention to provide improved flexible reclosable containers without the need for a continuous accurate seal of the continuous fastener profiles to the inner surface of the containers, or the extrusion of the continuous fastener profile integral with the container walls.
It is a further object of the present invention to provide flexible reclosable containers which may contain a plurality of sealed compartments so as to package a number of individual products together.
It is an additional object of the present invention to provide prefabricated strips of plastic film having continuous fastener profiles attached thereto so as to facilitate rapid manufacture of flexible reclosable containers at reduced cost.
Other objects, advantages, features and equivalent structures within the scope of the invention will become apparent to those skilled in the art in connection with the teachings of the principles thereof in the specification, claims and drawings.